This invention relates generally to a control tower for a gear select transmission shifter and, more particularly, to a control tower that can be used for either a lever selector or a push button selector. The control tower of this invention has been developed for use with a transmission (part number HD-4560P) and gear selectors (part numbers AS07-113 & AS07-114) manufactured by Allison Transmissions, of XXXX. However, it could be used for other transmissions and gear selectors of comparable size and design. Either the lever selector (part number AS07-114) or the push button selector (part number AS07-114) can shift the same transmission, for example, part number HD-4560P manufactured by Allison Transmissions. In the past, Allison Transmissions offered a lever type gear selector with an integral electronic control unit and a push button type gear selector with an integral electronic control unit. Control towers to accommodate those combined units required additional mounting parts to receive one or the other selectors. Also, when the control tower was used for the push button selector, it was mounted such that it extended from the cab floor at an angle, which resulted in locating the selector at an uncomfortable position for the operator of the vehicle. The special mounting parts increased the complexity and cost of assembly as well as the number of repair parts that must be inventoried. Also, a defective selector unit required replacing the entire selector-electronic control unit combination, which increased considerably the cost of repairing a gear selector, as well as requiring very expensive units to be carried in the replacement parts inventory.